Cluster Computing and Performance Measurement

There is a continual demand for greater computational power from computer systems than is currently possible. Areas requiring great computational speed include numerical simulation of scientific and engineering problems. Such problems often need huge quantities of repetitive calculations on large amount of data to give valid results. Cluster computing offers many advantages as a highly cost-effective and often scalable approach for high-performance computing in general. To achieve the full potential of high performance computing systems, centralized configuration services are the starting point. For a large scale of projects, cluster computing is required where it is supposed to be optimized for the system topology and management of the project. This paper presents the consequences of using cluster computing and performance management and the consequences without this technology. The experimental results of this paper highlight the affects of the design of this service and provide a comprehensive performance analysis of the project

Distributed Handler Architecture

Thesis (PhD) - Indiana University, Computer Sciences, 2007Over the last couple of decades, distributed systems have been demonstrated an architectural evolvement based on models including client/server, multi-tier, distributed objects, messaging and peer-to-peer. One recent evolutionary step is Service Oriented Architecture (SOA), whose goal is to achieve loose-coupling among the interacting software applications for scalability and interoperability. The SOA model is engendered in Web Services, which provide software platforms to build applications as services and to create seamless and loosely-coupled interactions. Web Services utilize supportive functionalities such as security, reliability, monitoring, logging and so forth. These functionalities are typically provisioned as handlers, which incrementally add new capabilities to the services by building an execution chain. Even though handlers are very important to the service, the way of utilization is very crucial to attain the potential benefits. Every attempt to support a service with an additive functionality increases the chance of having an overwhelmingly crowded chain: this makes Web Service fat. Moreover, a handler may become a bottleneck because of having a comparably higher processing time. In this dissertation, we present Distributed Handler Architecture (DHArch) to provide an efficient, scalable and modular architecture to manage the execution of the handlers. The system distributes the handlers by utilizing a Message Oriented Middleware and orchestrates their execution in an efficient fashion. We also present an empirical evaluation of the system to demonstrate the suitability of this architecture to cope with the issues that exist in the conventional Web Service handler structures

CPS에서의 물리 에러를 방지하는 안전 보장 메커니즘

학위논문(석사) -- 서울대학교대학원 : 공과대학 컴퓨터공학부, 2023. 2. 이창건.This paper considers a cyber-physical system with a so-called self-looping node that repeats the inner-loop for physical situation awareness, i.e., more loops for more harsh physical situations. Regarding such a self-looping node, we observe the existence of physical errors that make the looping useless and eventually cause a critical failure. To prevent such a critical failure despite a physical error, this paper proposes a novel mechanism by introducing time wall and safety backup. The time wall limits the time budget for the self-looping node so as to switch to the safety backup while still meeting the deadline to prevent critical failure despite physical errors. Our experiments through both simulation and actual implementation show that the proposed mechanism gives a comparable accuracy with the existing methods in normal cases while completely preventing critical failure in physical error cases.본 논문은 물리 상황 인지를 위해 내부 루프를 반복하는 자기반복 모듈(self-looping module)이 있는 사이버 물리 시스템을 고려한다. 자기반복 모듈은 더 높은 정확도를 위해 내부 루프를 반복하지만, 설계 단계에서 고려되지 못한 물리 환경을 마주하게 되면 루프를 반복하더라도 목표 정확도에 도달하지 못하는 물리 에러(physical error) 상황이 발생할 수 있다. 문제는 현재의 시스템의 경우 자기반복 모듈이 물리 에러를 인지하지 못하기 때문에 계속해서 루프를 반복하게 되고, 데드라인을 놓치는 등 시스템 자체의 치명적인 오류로 이어진다는 것이다. 본 논문에서는 물리 에러 상황에서도 최소한의 안전을 보장하기 위해 시간 장벽(time wall)과 안전 백업(safety backup)을 도입한 새로운 메커니즘을 제안한다. 시간 장벽은 자기반복 모듈의 최대 수행 시간으로, 자기반복 모듈이 시간 장벽만큼 실행했는데도 목표 정확도에 도달하지 못하면 안전 백업 모드로 전환한다. 본 논문은 시뮬레이션과 실제 자율주행 소프트웨어인 Autoware에 제안하는 메커니즘을 적용하여 제안하는 메커니즘이 치명적 오류를 완전히 방지하면서, 실제 자율주행 소프트웨어에도 적용 가능함을 보였다.1 Introduction 1 2 Related Work 5 3 Task and Resource Model 6 4 Safety Guarantee Mechanism Against Physical Errors 9 5 Classic Bound based Budget Analysis 13 5.1 Some Useful Computations on DAGs 14 5.2 Simple Solution 15 5.3 Solution with LP 18 6 CPC based Budget Analysis 21 6.1 Initial Budget Calculation 24 6.2 Binary Search for Finding the Optimal Budget 26 7 Generalize to Multiple Self-looping Nodes 30 7.1 Ambiguity in multiple self-looping nodes 30 7.2 Multiple Self-Looping Nodes: A Formal Model 32 7.3 Multiple self-looping nodes: Computing WCETs 34 8 Evaluation 37 8.1 Simulation with Synthetic DAG Workload 37 8.2 Implementation 42 9 Conclusion 46 9.1 Summary 46 9.2 Future Work 46 References 48석

Analogue neuromorphic systems.

This thesis addresses a new area of science and technology, that of neuromorphic systems, namely the problems and prospects of analogue neuromorphic systems. The subject is subdivided into three chapters. Chapter 1 is an introduction. It formulates the oncoming problem of the creation of highly computationally costly systems of nonlinear information processing (such as artificial neural networks and artificial intelligence systems). It shows that an analogue technology could make a vital contribution to the creation such systems. The basic principles of creation of analogue neuromorphic systems are formulated. The importance will be emphasised of the principle of orthogonality for future highly efficient complex information processing systems. Chapter 2 reviews the basics of neural and neuromorphic systems and informs on the present situation in this field of research, including both experimental and theoretical knowledge gained up-to-date. The chapter provides the necessary background for correct interpretation of the results reported in Chapter 3 and for a realistic decision on the direction for future work. Chapter 3 describes my own experimental and computational results within the framework of the subject, obtained at De Montfort University. These include: the building of (i) Analogue Polynomial Approximator/lnterpolatoriExtrapolator, (ii) Synthesiser of orthogonal functions, (iii) analogue real-time video filter (performing the homomorphic filtration), (iv) Adaptive polynomial compensator of geometrical distortions of CRT- monitors, (v) analogue parallel-learning neural network (backpropagation algorithm). Thus, this thesis makes a dual contribution to the chosen field: it summarises the present knowledge on the possibility of utilising analogue technology in up-to-date and future computational systems, and it reports new results within the framework of the subject. The main conclusion is that due to its promising power characteristics, small sizes and high tolerance to degradation, the analogue neuromorphic systems will playa more and more important role in future computational systems (in particular in systems of artificial intelligence)

Aerodynamics Optimization of the Univeniti Teknologi PETRONAS 'PERODUA Eco-ChaUenge 2011' Car

This is the construction and report on the experimentation of a shape-optimization method applied to aerodynamic design of a car. The scopes of study areas are in research, designing and analysis in computational fluid dynamics tool. The significance of this research would be important to evaluate the condition of the final model that posses the best drag coefficient This research starts by searching for any other relevant journal or article published by other researches and from there, the design would be review and useful information will be summarize and taken as an information to this research. From the data available from the model, the drag coefficient will be calculated manually and also by using software. CATIA v5, GAMBIT v2.2.30 and FLUENT v6.3.26 software are then used to design analyze the air flow behavior. The result from the computational fluid dynamics software will be compare with the result from wind tunnel experiment

A Control-Theoretic Design And Analysis Framework For Resilient Hard Real-Time Systems

We introduce a new design metric called system-resiliency which characterizes the maximum unpredictable external stresses that any hard-real-time performance mode can withstand. Our proposed systemresiliency framework addresses resiliency determination for real-time systems with physical and hardware limitations. Furthermore, our framework advises the system designer about the feasible trade-offs between external system resources for the system operating modes on a real-time system that operates in a multi-parametric resiliency environment. Modern multi-modal real-time systems degrade the system’s operational modes as a response to unpredictable external stimuli. During these mode transitions, real-time systems should demonstrate a reliable and graceful degradation of service. Many control-theoretic-based system design approaches exist. Although they permit real-time systems to operate under various physical constraints, none of them allows the system designer to predict the system-resiliency over multi-constrained operating environment. Our framework fills this gap; the proposed framework consists of two components: the design-phase and runtime control. With the design-phase analysis, the designer predicts the behavior of the real-time system for variable external conditions. Also, the runtime controller navigates the system to the best desired target using advanced control-theoretic techniques. Further, our framework addresses the system resiliency of both uniprocessor and multicore processor systems. As a proof of concept, we first introduce a design metric called thermal-resiliency, which characterizes the maximum external thermal stress that any hard-real-time performance mode can withstand. We verify the thermal-resiliency for the external thermal stresses on a uniprocessor system through a physical testbed. We show how to solve some of the issues and challenges of designing predictable real-time systems that guarantee hard deadlines even under transitions between modes in an unpredictable thermal environment where environmental temperature may dynamically change using our new metric. We extend the derivation of thermal-resiliency to multicore systems and determine the limitations of external thermal stress that any hard-real-time performance mode can withstand. Our control-theoretic framework allows the system designer to allocate asymmetric processing resources upon a multicore proiii cessor and still maintain thermal constraints. In addition, we develop real-time-scheduling sub-components that are necessary to fully implement our framework; toward this goal, we investigate the potential utility of parallelization for meeting real-time constraints and minimizing energy. Under malleable gang scheduling of implicit-deadline sporadic tasks upon multiprocessors, we show the non-necessity of dynamic voltage/frequency regarding optimality of our scheduling problem. We adapt the canonical schedule for DVFS multiprocessor platforms and propose a polynomial-time optimal processor/frequency-selection algorithm. Finally, we verify the correctness of our framework through multiple measurable physical and hardware constraints and complete our work on developing a generalized framework

An accurate prefetching policy for object oriented systems

PhD ThesisIn the latest high-performance computers, there is a growing requirement for accurate prefetching(AP) methodologies for advanced object management schemes in virtual memory and migration systems. The major issue for achieving this goal is that of finding a simple way of accurately predicting the objects that will be referenced in the near future and to group them so as to allow them to be fetched same time. The basic notion of AP involves building a relationship for logically grouping related objects and prefetching them, rather than using their physical grouping and it relies on demand fetching such as is done in existing restructuring or grouping schemes. By this, AP tries to overcome some of the shortcomings posed by physical grouping methods. Prefetching also makes use of the properties of object oriented languages to build inter and intra object relationships as a means of logical grouping. This thesis describes how this relationship can be established at compile time and how it can be used for accurate object prefetching in virtual memory systems. In addition, AP performs control flow and data dependency analysis to reinforce the relationships and to find the dependencies of a program. The user program is decomposed into prefetching blocks which contain all the information needed for block prefetching such as long branches and function calls at major branch points. The proposed prefetching scheme is implemented by extending a C++ compiler and evaluated on a virtual memory simulator. The results show a significant reduction both in the number of page fault and memory pollution. In particular, AP can suppress many page faults that occur during transition phases which are unmanageable by other ways of fetching. AP can be applied to a local and distributed virtual memory system so as to reduce the fault rate by fetching groups of objects at the same time and consequently lessening operating system overheads.British Counci

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy

Book of abstracts of the 15th International Symposium of Croatian Metallurgical Society - SHMD \u272022, Materials and metallurgy, Zagreb, Croatia, March 22-23, 2022. Abstracts are organized in four sections: Materials - section A; Process metallurgy - Section B; Plastic processing - Section C and Metallurgy and related topics - Section D